mirror of
https://github.com/kuhyx/testsAndMisc.git
synced 2026-11-12 15:30:57 +01:00
Krzysztof kuhy Rudnicki
7c14cfca61
23 assertions over 8 cases covering both tweak_vm_sysctl and tweak_network_sysctl: the skip path, the write-when-the-drop-in-is- missing path that a naive "nothing to do" check gets wrong, the value-differs path, an unreadable-sysctl path, and the tcp_bbr guard. arch_desktop_harness.sh is the third family harness, supplying the globals and apply_tweak that live in optimize_arch_desktop.sh rather than in any lib. arch_cpu.sh and arch_hardware.sh will reuse it. SYSCTL_DROPIN_DIR defaults to the real /etc/sysctl.d, matching the seam ubuntu_perf_more.sh and arch_perf_fixes.sh already carry; the suite runs un-jailed in ci_mirror.sh and CI, so a bind mount would protect nothing. Both real drop-ins keep their Mar 2 mtimes. _t_run lands in lib_test_core.sh because `out="$(func)"` forks a subshell and kcov never registers a lib whose first execution happens inside one -- measured as 0 lines via $( ) against 54 lines via a direct call. arch_sysctl.sh STAYS on the coverage allowlist: it still reports "kcov instrumented no lines" through the jail, while ubuntu_perf_more.sh measures 32/32 in the same worktree and the same invocation. The tests are real and green; the coverage number is not yet obtainable, and the exemption may only come off once it is. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
125 lines
4.0 KiB
Bash
Executable File
125 lines
4.0 KiB
Bash
Executable File
#!/bin/bash
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# VM and network sysctl tuning.
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#
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# Sourced by optimize_arch_desktop.sh; split out to keep it under the 250-line
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# cap. Sourced rather than run, so it inherits the caller's strict mode
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# and the variables defined above the source line.
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# ===================================================================
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# 3. Memory & swap tuning via sysctl
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# ===================================================================
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tweak_vm_sysctl() {
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# SYSCTL_DROPIN_DIR defaults to the real directory and is overridden only
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# by the test harness, which runs un-jailed in ci_mirror.sh and in CI.
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local dropin="${SYSCTL_DROPIN_DIR:-/etc/sysctl.d}/90-desktop-performance.conf"
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# Desktop workloads: low swappiness, aggressive VFS caching, tuned dirty ratios
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local -A params=(
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["vm.swappiness"]="10"
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["vm.vfs_cache_pressure"]="50"
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["vm.dirty_ratio"]="15"
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["vm.dirty_background_ratio"]="5"
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["vm.dirty_writeback_centisecs"]="1500"
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["vm.page-cluster"]="0"
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)
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local needs_update=false
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local key
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for key in "${!params[@]}"; do
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local current
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current=$(sysctl -n "$key" 2>/dev/null || true)
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if [[ $current != "${params[$key]}" ]]; then
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needs_update=true
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break
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fi
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done
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if [[ $needs_update == "false" && -f $dropin ]]; then
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log_ok "VM sysctl parameters already tuned — skipping."
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return 0
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fi
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cat >"$dropin" <<'VMEOF'
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# Desktop performance tuning — managed by optimize_arch_desktop.sh
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#
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# vm.swappiness=10 — prefer keeping data in RAM over swapping
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# vm.vfs_cache_pressure=50 — favor keeping inode/dentry caches (speeds up file operations)
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# vm.dirty_ratio=15 — allow up to 15% RAM dirty before synchronous writeback
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# vm.dirty_background_ratio=5 — start async writeback at 5% dirty
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# vm.dirty_writeback_centisecs=1500 — flush dirty pages every 15s (less I/O churn)
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# vm.page-cluster=0 — read one page at a time from swap (reduces latency on SSD)
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vm.swappiness = 10
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vm.vfs_cache_pressure = 50
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vm.dirty_ratio = 15
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vm.dirty_background_ratio = 5
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vm.dirty_writeback_centisecs = 1500
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vm.page-cluster = 0
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VMEOF
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sysctl --system >/dev/null 2>&1
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return 0
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}
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# ===================================================================
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# 4. Network: TCP BBR + fastopen + buffer tuning
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# ===================================================================
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tweak_network_sysctl() {
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local dropin="${SYSCTL_DROPIN_DIR:-/etc/sysctl.d}/91-desktop-network.conf"
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# Check if BBR module is available
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if ! modprobe tcp_bbr 2>/dev/null; then
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log_warn "tcp_bbr kernel module unavailable — skipping network tuning."
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return 0
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fi
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local -A params=(
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["net.core.default_qdisc"]="fq"
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["net.ipv4.tcp_congestion_control"]="bbr"
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["net.ipv4.tcp_fastopen"]="3"
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["net.core.rmem_max"]="16777216"
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["net.core.wmem_max"]="16777216"
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["net.ipv4.tcp_rmem"]="4096 1048576 16777216"
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["net.ipv4.tcp_wmem"]="4096 1048576 16777216"
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["net.ipv4.tcp_mtu_probing"]="1"
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)
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local needs_update=false
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local key
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for key in "${!params[@]}"; do
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local current
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current=$(sysctl -n "$key" 2>/dev/null || true)
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# Normalize whitespace for comparison (kernel uses tabs)
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current=$(echo "$current" | xargs)
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local expected
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expected=$(echo "${params[$key]}" | xargs)
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if [[ $current != "$expected" ]]; then
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needs_update=true
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break
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fi
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done
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if [[ $needs_update == "false" && -f $dropin ]]; then
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log_ok "Network sysctl parameters already tuned — skipping."
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return 0
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fi
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cat >"$dropin" <<'NETEOF'
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# Network performance tuning — managed by optimize_arch_desktop.sh
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#
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# BBR congestion control — better throughput and lower latency than cubic
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# TCP fastopen — saves one RTT on repeated connections (both client and server)
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# Larger buffers — helps on high-bandwidth or high-latency links
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net.core.default_qdisc = fq
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net.ipv4.tcp_congestion_control = bbr
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net.ipv4.tcp_fastopen = 3
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net.core.rmem_max = 16777216
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net.core.wmem_max = 16777216
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net.ipv4.tcp_rmem = 4096 1048576 16777216
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net.ipv4.tcp_wmem = 4096 1048576 16777216
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net.ipv4.tcp_mtu_probing = 1
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NETEOF
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sysctl --system >/dev/null 2>&1
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return 0
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}
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